The present invention relates to a tone generator control apparatus and program suited for application to electronic wind instruments.
Generally, with air-lead musical instruments, such as flutes and piccolos, there has been employed so-called “octave-specific playing” for properly playing two different tones, having a same pitch name but different in octave with a same fingering pattern or state. In FIG. 22, there are shown a fingering pattern or state for generating or sounding notes “E” of first and second octaves (indicated by A in the figure), and a fingering state for sounding notes “F” of the first and second octaves (indicated by B in the figure). For example, when notes “E” of the first and second octaves are to be generated with the fingering state shown in FIG. 22, a human player blows air relatively weakly for the E note of the first octave but blows air relatively strongly for the E note of the second octave. Embouchure too slightly differs between the first and second octaves.
Regarding the conventional air-lead musical instruments, such as organ pipes, there has been obtained various physical information about generation of tones (see, for example, “Study of Organ Pipe and its Application to Underwater Sound Source”, by Shigeru Yoshikawa, doctoral thesis for Tokyo Institute of Technology, 1985; this literature will hereinafter be referred to as “Non-patent Literature 1”). FIG. 23 shows physical information about a tone generation section of a pipe organ. In the figure, reference character AF indicates an air flow input to the pipe organ's tone generation section, SL indicates a slit, and EG indicates an edge. Examples of the physical information include an initial velocity U(0) (m/s) of an air jet at an outlet of the slit SL, final velocity U(d) (m/s) of the jet at the edge EG, distance d (m) between the slit SL and the edge EG, time τe (sec) of air jet transfer from the slit to the edge, tone generating frequency fso (Hz), etc. In the figure, relationship between a distance x from the slit and jet flow velocity U(x) (flow velocity distribution of an air jet) is shown below the pipe organ's tone generation section. The jet flow velocity U(x) gradually lowers from the initial jet velocity U(0) to the final jet velocity U(d) as illustrated in FIG. 23.
In Non-patent literature 1, there is a description to the effect that a tone generating octave of the air lead of an air-lead musical instrument, such as a flute or organ pipe, can be determined by a current tone generation mode and traveling angle of an air jet. In Non-patent literature 1, the jet traveling angle θe can be expressed by Mathematical Expression 1 below using the above-mentioned jet transfer time τe and tone generating frequency fso (or tone generating angular frequency ωso=2π·fso).σe=ωso×τe   [Mathematical Expression 1]where ωso=2π·fso.
Further, the jet transfer time τe can be expressed by Mathematical Expression 2 below using the above-mentioned slit-to-edge distance d and jet flow velocity U(x).τe=∫0d1/U(x)dx   [Mathematical Expression 2]
The jet transfer time τe can also be determined through the conventionally-known trapezoidal approximation method instead of the integral calculation of Mathematical Expression 2 above. Namely, The jet transfer time τe can also be determined by Mathematical Expression 3 below assuming that Ui indicates a jet flow velocity (m/s) at a distance x (=i·Δx (m) (i=1, 2, . . . n)) from the slit SL. The jet transfer time τe determined by Mathematical Expression 3 corresponds to an area Sd of a hatched section in FIG. 24. In order to accurately perform the calculation of Mathematical Expression 3 with a high accuracy, it is desirable that Δx be set at a sufficiently small value, such as 0.1 (cm) and the jet flow velocity be detected at many points.
                                          τ            ⁢                                                  ⁢            e                    ≈                                    ∑                              i                =                1                            n                        ⁢                                          (                                  1                  /                  2                                )                            ⁢                              (                                                      1                    /                                          U                                              i                        -                        1                                                                              +                                      1                    /                                          U                      i                                                                      )                            ⁢              Δ              ⁢                                                          ⁢              x                                      ⁢                                                      [                  Mathematical          ⁢                                          ⁢          Expression          ⁢                                          ⁢          3                ]            
FIG. 25 shows octave variation based on the tone generation mode and jet traveling angle θe, where the tone generation mode is shown as switchable between a primary mode and secondary mode. The primary mode is a mode in which a tone of a given pitch name is generated in a predetermined octave, while the secondary mode is a mode in which the tone generated in the primary mode is generated with the pitch raised by one octave.
Once a jet of an initial velocity U(0) is produced in a state S1, tone generation in the primary mode is started at a time point S2 where the jet traveling angle θe equals 3π/2 (θe=3π/2). Then, in a time period S3 when the jet traveling angle θe degreases from π, through 3π/4, . . . , toward π/2, a tone generating frequency gradually increases so that a tone pitch and color are also caused to vary in an actual air-lead instrument, although not specifically described in Non-patent Literature 1. At a time point S4 where the jet traveling angle θe equals π/2, the tone generation mode jumps to the secondary mode (one octave up). During the jump period S5, the tone generating frequency doubles so that the jet traveling angle θe too doubles up to π.
Tone generation in the secondary mode is started at a time point S6 when the jet traveling angle θe is π. Then, during a time period S7 when the jet traveling angle θe increases from π to 3π/2, the tone generating frequency gradually decreases so that the tone pitch and color are also caused to vary, although not specifically described in Non-patent Literature 1. At a time point S8 when the jet traveling angle θe equals 3π/2, the mode jumps to the primary mode (i.e., one octave down). During the downward jump period S9, the tone generating frequency decreases by half, and thus, the jet traveling angle θe decreases by half to 3π/4. Note that the leftward direction in FIG. 25 is a direction in which the jet flow velocity U(x) increases and is also a direction in which the distance d between the slit and the edge decreases.
Regarding jet flow velocity distribution, it has been known, for example, that (a) the greater the initial jet velocity, the greater the attenuation of the jet flow velocity U(x) and that (b) in a case where the initial jet velocity is small and the distance d between the slit and the edge is small, the attenuation of the jet flow velocity U(x) may be ignored (see for example, “Experimental Consideration about Jet Flow Velocity Distribution and Tone Generating Characteristic of Air-lead Instrument”, by Keita Arimoto, mater's thesis for Kyushu Institute of Design, 2001; this literature will hereinafter be referred to as “Non-patent Literature 2”).
Further, there have been known tone generator control apparatus which control a physical model tone generator, simulative of an air-lead instrument, in response to operation on a keyboard (e.g., Japanese Patent Application Laid-open Publication No. HEI-67675 corresponding to U.S. Pat. No. 5,521,328; this publication will hereinafter be referred to as “Patent Literature 1”). Also known are various types of wind instruments provided with a mouse piece or other air-blowing (or playing) input section, such as the type where an air flow is detected via a breath sensor to control a start and end of tone generation (e.g., Japanese Patent Application Laid-open Publication No. SHO-64-77091; this publication will hereinafter be referred to as “Patent Literature 2”); the type where tone-characteristic switching control is performed in accordance with an intensity of breath (e.g., Japanese Patent Application Laid-open Publication No. HEI-5-216475; this publication will hereinafter be referred to as “Patent Literature 3”); the type where a tone pitch is controlled in accordance with a direction of exhaled or expiratory air blown into the mouse piece (e.g., Japanese Patent Application Laid-open Publication No. HEI-7-199919; this publication will hereinafter be referred to as “Patent Literature 4”); and the type where tone pitch information and tone volume information is obtained from a flow velocity of expiratory air blown into the mouse piece and total amount of the expiratory air, respectively (e.g., Japanese Patent Application Laid-open Publication No. 2002-49369; this publication will hereinafter be referred to as “Patent Literature 5”).
The electronic musical instrument disclosed in Patent Literature 1 above is constructed to create control information of a thickness, flow velocity, inclination, etc. of a jet on the basis of key operation information acquired from a keyboard, then convert the control information into tone generator control parameters and thence supply these tone generator control parameters to a physical model tone generator. With the thus-constructed electronic musical instrument, it is not possible to execute a performance in accordance with blowing inputs to the mouse piece.
The electronic musical instruments disclosed in Patent Literature 2 to Patent Literature 5, on the other hand, are capable of executing a performance in accordance with blowing inputs, but they do not permit different playing styles to properly play different octaves (i.e., “octave-specific playing styles”) as played with an ordinary flute or other air-lead instrument. It would be conceivable to permit different playing styles to properly play different octaves (octave-specific playing styles) by applying the information and technique disclosed in Non-patent literature 1; however, in the case where the information and technique disclosed in Non-patent literature 1 is applied as-is, the following problems would be encountered.
(1) If octave-switching control is performed on the basis of a current tone generating mode and jet traveling angle θe, there arises a need to acquire an actual tone generating frequency and substitute the thus-acquired actual tone generating frequency into Mathematical Expression 1 above. However, because the electronic musical instruments are not natural musical instruments. it is not possible to acquire such an actual tone generating frequency.
(2) In order to obtain a jet transfer time τe with a high accuracy, it is necessary to sense a jet flow velocity at a number of points; however, it is practically difficult to position a number of flow velocity sensors along a jet flow path.